The main opposition Democratic United Party will not be fielding a candidate for Seoul’s Nowon C constituency in the April 24 by-elections in what is seen as a passive display of support for its former ally and rival Ahn Cheol-soo, who declared his candidacy in the district.

The decision set the stage for a three-way race between frontrunner Ahn, the ruling Saenuri Party and the leftist Progressive Justice Party.

The constituency in northern Seoul has been vacant since the Supreme Court confirmed former PJP lawmaker Roh Hoe-chan’s conviction for disclosing illegally obtained information in February. His wife Kim Ji-seon is running in the election.

“After much consideration between the rightfulness of putting up a candidate and the view that the Park Geun-hye government must be judged, the DUP has decided to not nominate a candidate,” DUP spokesman Rep. Jung Sung-ho told reporters on Monday.

He added that former independent presidential candidate Ahn’s role in last year’s presidential campaign was highly regarded.

In the run up to the Dec. 19 election, Ahn forfeited in favor of the DUP’s Rep. Moon Jae-in and is now running for the Nowon C constituency as an independent candidate.

The DUP’s decision was met with criticism that the main opposition was trying to avoid a possible defeat.

“This is unbecoming of a political party, and it is against responsible politics,” Saenuri Party spokesman Rep. Lee Sang-il said in a statement saying that the decision was cowardly.

“Most of the public and the Nowon residents will not give their trust to a political group that is obsessed with political trickery designed to win elections.”

The decision has also raised criticism within the party.

Lee, who is running for the party chairmanship in May, criticized the decision saying that the DUP’s inability to run its own candidate in the constituency was “unspeakably painful and horrific.”

While Lee said that he understood that the party’s leadership had no other choice, similar decision making should be avoided in the future.

He said that the party’s decision was in part repayment for Ahn’s contribution to last year’s presidential campaign, and in part a measure to prevent a Saenuri Party candidate winning the constituency.

“This should be the last time candidate nomination is not made in this way,” Lee said in a statement.

The development has been met with very different reactions from the two non-conservative candidates who have announced their desire for the Nowon C seat.

Former presidential candidate Ahn Cheol-soo responded to the development in characteristically ambiguous manner.

“I think it is good to combine the will of many people. I will do my best to win the hearts of the residents of the area for new politics,” Ahn said Monday.

Progressive Justice Party candidate Kim appeared to have interpreted DUP’s decision very differently.

“I send sincere condolences to the DUP’s Lee Dong-sup who was preparing to run. (I) will inherit the will of the voters who supported the DUP and achieve victory,” Kim wrote on her Twitter account. Lee Dong-sup is the chief of the DUP committee for the Nowon C constituency, and had announced that he would run in the upcoming by-election.

Both Ahn and Kim, however, have not ruled out forming a unified campaign for the progressive bloc.

By Choi He-suk (cheesuk@heraldcorp.com)